Conventional liquid crystal displays mounted in mobile electronic devices, such as mobile phones and smartphones, implement display of a visible image by using a light source, such as a backlight.
In the above-mentioned mobile electronic devices, when an interrupt such as an incoming call or a reception of an electronic mail occurs, a display module is turned on to produce a display for notifying a user of the interrupt. However, even when the interrupt is not necessary or less important for a user, the occurrence of the interrupt uniformly causes the display module to be turned on to produce the display. Hence, there is a problem in which the mobile electronic devices wastefully consume electric power.